Influence of preceding crop and tillage system on forage yield and quality of selected summer grass and legume forage crops under arid conditions

Among the crop production factors,preceding crop and tillage management affect the sustainable use of soil resources and ultimately crop growth and productivity.This study aimed at investigating the impact of preceding winter crops(grass or legume)and different tillage systems on forage yield,quality and nutritive values of three summer grass(Sudan grass,pearl millet and teosinte)and two legume forage crops(cowpea and guar)under arid conditions.The results exhibited that growing forage crops after legumes(as berseem clover)produced the highest fresh and dry forage yields and quality attributes compared with grasses(as wheat)with the exception of crude fiber content,which was decreased.Moreover,tillage practices showed positive impact on forage yields and quality attributes.The maximum forage yields and quality parameters were recorded under conventional tillage(CT)practice compared with reduced tillage(RT)and no-tillage(NT)systems.Among the evaluated crops,the highest yields of fresh forage,dry forage,crude fiber,crude protein and total digestible nutrient were exhibited by grass forage crops(Sudan grass,pearl millet and teosinte),whereas the highest crude protein content and the digestible energy values were produced by legume forage crops(cowpea and guar).The maximum fresh forage,dry forage,crude fiber,crude protein,total digestible nutrient and digestible crude protein yields were produced by pearl millet followed by Sudan grass under CT and RT after berseem clover.The highest net return was recorded by sowing pearl millet after berseem clover and applying CT followed by RT practices,which could be recommended for the commercial production.Moreover,it could be assumed that the combination of growing grass forage crops after legume crops under CT or RT systems could enhance forage crop yield and quality with an improvement in soil properties for sustainable agriculture with low cost and the highest net income.

Effects of Different Preceding Crops on Soil Micro-ecological Environment and Yield of Cucumber

Pepper, celery, eggplant and tomato were used as preceding crops to study their effects on the yield, soil microorganism quantity and soil enzyme activities of cucumber. Results showed that four preceding crops all increased soil microorganism quantity in cucumber, but decreased population of Fusarium oxysporum. The effect of pepper was more significant than that of the others Populations of soil bacteria, fungi and actinomyces of pepper treatment were significantly higher than those of the other treatments, except that the populations of fungi had no significant difference with celery and eggplant treatments on 50 days after transplanting, while that of Fusarium oxysporum was fewer than that of the other treatments. The soil microorganism quantity in celery and eggplant treatment was more significant than tomato, but lower population of Fusarium oxysporum. Four preceding crops all increased sol enzyme activities, lnvertase and urease activities of pepper treatment were significantly higher than those of the other treatments, catalase activities of pepper, celery and eggplant treatments were significantly higher than those of tomato and the control treatments All preceding crops remarkably increased cucumber yield, with pepper as the highest. Comparing with the control, cucumber yields of pepper, celery and eggplant treatments increased by 24.9%, 13.6% and 11.9%, respectively. Results suggested that four preceding crops all improved soil microbial ecology and increased cucumber yield. The pepper was the most suitable preceding crop, then followed by celery and eggplant. Tomato had the similar effect as the control.

Effects of Root Growth of Deep and Shallow Rooting Rice Cultivars in Compacted Paddy Soils on Subsequent Rice Growth

Rice is often grown as multiple seasons in one year,alternating between flooded and upland systems.A major constraint,introduced from the flooded system,is a plough pan that may decrease rooting depth and productivity of follow-on upland rice.Roots penetrating the plough pan under flooded rice system can leave a legacy of weaker root growth pathways.Deeper rooting rice cultivars could have a bigger impact,but no direct evidence is available.To explore whether a deep rather than a shallow rooting rice cultivar grown in a flooded cropping cycle benefited deeper root growth of follow-on rice in an upland,reduced tillage cropping cycle,a simulated flooded paddy in greenhouse was planted with deep(Black Gora) and shallow(IR64) rooting cultivars and a plant-free control.Artificial plough pans were made in between the topsoil and subsoil to form different treatments with no plough pan(0.35 MPa),soft plough pan(1.03 MPa) and hard plough pan(1.70 MPa).After harvest of this ‘first season’ rice,the soil was drained and undisturbed to simulate zero-tillage upland and planted rice cultivar BRRI Dhan 28.The overall root length density(RLD),root surface area,the numbers of root tips and branching of BRRI Dhan 28 did not vary between plough pan and no plough pan treatments.Compared with the shallow rooting rice genotype,the deep rooting rice genotype as ‘first season’ crop produced 19% greater RLD,34% greater surface area and 29% more branching of BRRI Dhan 28 in the subsoil.In the topsoil,however,BRRI Dhan 28 had 28% greater RLD,35% greater surface area and 43% more branching for the shallow rather than deep rooting genotype planted in the ‘first season’.The results suggested that rice cultivar selection for a paddy cycle affects root growth of a follow-on rice crop grown under no-till,with benefits to subsoil access from deep rooting cultivars and topsoil proliferation for shallow rooting cultivars.