Crop residue, manure and fertilizer in dryland maize under reduced tillage in northern China: I grain yields and nutrient use efficiencies

Abstract

The rapidly increasing population and associated quest for food and feed in China has led to increased soil cultivation and nitrogen (N) fertilizer use, and as a consequence to increased wind erosion and unbalanced crop nutrition. In the study presented here, we explored the long-term effects of various combinations of maize stover, cattle manure and nitrogen (N) and phosphorus (P) fertilizer applications on maize (Zea mays L.) yield and nutrient and water use efficiencies under reduced tillage practices. In a companion paper, we present the effects on nutrient balances and soil fertility characteristics. The ongoing factorial field trial was conducted at Shouyang Dryland Farming Experimental Station in northern China from 1993 onwards. The incomplete, determinant-optimal design comprised 12 treatments, including a control treatment, in duplicate. Grain yields and N, P, and potassium (K) uptakes and N, P and K use efficiencies were greatly influenced by the amount of rain during the growing season (GSR), and by soil water at sowing (SWS). There were highly significant interactions between GSR and added stover and manure, expressed in complex annual variations in grain yield and N, P and K use efficiencies. Annual mean grain yields ranged from 3,000 kg ha À1 to 10,000 kg ha À1 and treatment mean yields from 4,500 kg ha À1 to 7,000 kg ha À1 . Balanced combination of stover (3,000-6,000 kg), manure (1,500-6,000 kg) and N fertilizer (105 kg) gave the highest yield. Stover and manure were important for supplying K, but the effects differed greatly between years. Overall mean N recovery efficiency (NRE) ranged from 28% to 54%, depending on N source. NRE in wet years ranged from 50% to 90%. In conclusion, balanced combinations of stover, manure and NP fertilizer gave the highest yield and NRE. Reduced tillage with adding stover and manure in autumn prior to ploughing is effective in minimizing labor requirement and wind erosion. The potentials of split applications of N fertilizer, targeted to the need of the growing crop (response farming), should be explored to further increase the N use efficiency.

Crop residue, manure and fertilizer in dryland maize under reduced tillage in northern China: II nutrient balances and soil fertility

“…Maize stover applications were 0, 879, 3,000, 5,121 and 6,000 kg ha À1 . Cattle manure applications were 0, 1,500, 3,000, 4,500 and 6,000 kg ha À1 (also Wang et al 2007a). …”

“…Plant analyses of N and P were started in 1993, that of K in 1997. Grain yields and N, P and K uptakes have been described in detail in Wang et al (2007a).…”

“…Note, treatments are arranged in the order of increasing grain yields (see text). Values with the same letter within a column are not significantly different at the 5% level Treatment Added F, S and M, respectively, (kg ha onwards and because variations in SWS and GSR were relatively small during the period 1997-2004 (Wang et al 2007a). Annual variations in balances of effective C were relatively small, with maximal differences between years within treatments of 500 kg ha À1 year À1 , nearly independent of the choice of decay coefficient for SOM (Fig.…”

“…The reduced tillage practice has been shown to be highly effective in decreasing wind erosion (Cai et al 2002;Wang et al 2006). Effects of applying organic residues and mineral fertilizer in autumn on grain yields and nitrogen (N), phosphorus (P) and potassium (K) use efficiencies have been reported in Wang et al (2007a). This paper discusses partial N, P and K balances and the changes in soil organic matter (SOM) and soil fertility indices for P and K.…”

“…With time, negative N balances tended to become less negative and positive balances more positive, because grain yields and N uptake tended to decrease over time (Wang et al 2007a). This decreasing trend was most clear in treatments providing little or no NP fertilizer (treatments 8, 12 and 3).…”